JP2007507966A - Transmission of digital television by error correction - Google Patents

Abstract

A multimedia stream system includes a transmitter and a multimedia data stream receiver. The transmitter at receives raw multimedia data and generates uniform error correction data and a standard multimedia data stream. The multimedia data stream receiver receives the standard multimedia data stream containing encoded multimedia data and the uniform error correction data for error correction of encoded multimedia data.

Description

  The present invention relates to the field of transmission of digital television through noisy media with error correction. Noise in this medium is erroneous in received data that requires error correction for reasonable display quality.

  Digital multimedia data streams such as MPEG streams are extremely vulnerable to transmission errors. If no error correction is provided, even a 1-bit error will prevent the decoding of important parts of the MPEG stream. Proposed digital television standards such as the proposed ATSC standard for DTV and the proposed DVB standard provide FEC (Forward Error Correction) data that can correct some errors that occur during transmission. To do. Error correction data is typically redundant data in the form of parity bits. The amount of error that can be corrected by the error correction scheme depends on the amount of error correction data provided in the scheme. Small errors, such as random single-bit errors, are more common than large burst errors so that a small amount of error correction data is sufficient to correct most errors. Also, error correction data that is not an actual amount can eliminate all possible transmission errors. These proposed standards are therefore based on a trade-off between error correction robustness and the amount of error correction data that needs to be transmitted.

  The proposed digital television technology provides acceptable reception for low noise transmission channels such as provided by current cable and satellite television transmission schemes. However, there is a need to provide more robust error correction of television transmissions through noisy channels such as extended cable systems, terrestrial broadcasts, Internet transmissions, cell phone transmissions, and wireless network transmission channels.

  In recent years, non-uniform or prioritized protection schemes for video data have been widely proposed in the literature. These schemes take advantage of the fact that errors in one part of a digital multimedia stream are more serious than errors in other parts of the stream. Errors in important parts of the digital multimedia stream cause loss of important data, for example, errors in the headers of MPEG video I frames prevent decoding of the entire group of video frames, and errors in audio frames It may become a word that cannot be understood. However, data in less important parts of the digital multimedia stream may not even be perceptible.

  In the proposed heterogeneous protection scheme, the digital multimedia stream is divided into different parts of different data types that contribute different amounts to the quality of the display. Then, some of the data types that contribute a lot to the quality of the presentation, for example, provide more data redundancy or provide more retries to correctly transmit more important data types Thus, it is more robust than some of the other types of data. Generally in these schemes, the transmission channel used to transmit the multimedia stream is divided over time for different portions of the video signal.

  A channel is part of a communication resource in which communication signals are transmitted, and transmission of signals through one channel is substantially independent of transmission of other channels through other channels of communication resources. Channel communication is the transmission of a signal through a channel. A channel has a predetermined characteristic, such as a predetermined transmission rate or bandwidth, that is substantially independent of communication through other channels. For example, a channel is a conductive path through which electrical signals are transmitted or a frequency band in which electromagnetic signals are transmitted. Only one transmitter at a time can transmit information over the same channel. A resource may be a medium or a series of different media. A channel may be divided or sliced into multiple channels by time and / or frequency slicing the channel so that different transmitters can independently transmit different signals through different slices of the same channel. Each slice of a channel that provides substantially independent transmission is also called a channel. Here, the channel is defined from the perspective of the transmitter and the receiver. That is, a communication resource in which a signal is transmitted is considered a channel as long as signal transmission and reception are substantially independent of communication through other channels.

  Communication through a switch packet network such as the Internet is not limited to channels in a switch packet network, but typically such communication is a channel inside or outside the Internet to meet the previous definition of channel communication. Limited to

Those skilled in the art are directed to the following references which are incorporated herein by reference in their entirety.
・ “PES packet and elementary streams” in “Comprehensive MPEG2 Video
Compression Tutorial ”by Wayne E. Bretl and Mark Fimoff, January 15, 2000, at www.bretl.com
・ “ATSC Standard A / 53: Digital Television Standard”, August 2001, at
http://www.atsc.org
In the multimedia stream transmitter of the present invention, the stream transmitter receives a standard multimedia data stream. The stream includes encoded multimedia data variants and uniform error correction data that are effective to error-correct the encoded multimedia data. Uniform error correction data provides substantially the same robustness of error correction for each portion of the encoded multimedia data of a standard multimedia data stream. The transmitter selects certain stream portions of the encoded multimedia data stream, but not other stream portions of the encoded multimedia data stream. The selection depends on the importance of the selected stream portion to the correct decoding of the encoded multimedia data. The transmitter generates selection map data indicating which stream has been selected. The transmitter also generates further unequal error correction data for error correction of the selected stream portion, and does not generate such further error correction data for other unselected stream portions. The transmitter transmits a standard multimedia stream through the first channel and transmits enhancement data including selection map data and further unequal error correction data through the second channel. The second channel is a channel that is different from the first channel, that is, the transmission of the information signal through the first channel is independent of the transmission of the information signal through the second channel.

  In the multimedia data receiver of the present invention, the receiver receives a standard multimedia data stream from a first channel and enhancement data from a second channel. The receiver selectively error corrects selected portions of the standard multimedia data stream according to the selection map using further unequal error correction data. The receiver also uniformly corrects all encoded multimedia data using uniform error correction data.

  The advantage of the combination of uniform error correction in combination with further unequal error protection for important parts of the multimedia data is that most errors in the less important parts of the multimedia data are corrected and more Even widespread errors include being corrected in a more important part of the encoded multimedia data. The advantage of transmitting a standard multimedia data stream with uniform error correction through the first channel and with non-uniform error correction through the second channel is that the standard multimedia data stream with uniform error correction is Is compatible with receivers that receive only a standard stream from the first channel and do not receive enhancement data from the second channel. Thus, the transmitter of the present invention is used for standard receivers that do not utilize the present invention. In a broadcast embodiment where multiple receivers at different locations receive signals from the same transmitter of the present invention, one receiver receives a noisy signal and other receivers receive a noisy signal. The machine utilizes the present invention to obtain improved reception quality, and less complex receivers that do not utilize the present invention are used to receive low noise signals.

  The transmitter may generate a third error correction data portion that is effective for performing error correction on the enhancement data. The third error correction data provides substantially the same uniform error correction robustness for each portion of the enhancement data. The receiver may perform error correction on the enhancement data before error correcting a selected portion of the standard stream. The transmitter may generate an enhancement stream of enhancement transmission frames. Each enhancement transmission frame may include a fixed size portion of enhancement data and a fixed size portion of third error correction data.

  A standard stream may include elementary stream packets of a fixed size, and the packet includes a packet header and a packet data portion, respectively. The packets may include video packets that include video data in their packet data portions, and audio packets that include audio data in their packet data portions.

  A standard stream is organized into standard transmission frames of fixed size, each standard transmission frame comprising a fixed size portion of encoded multimedia data and uniform error correction data. Includes a fixed size portion of (uniform error correction data). The uniform error correction data included in each frame may be for performing error correction on the encoded multimedia data included in the same frame.

  Standard transmission frames are many that efficiently generate and organize selection map data and unequal error correction data for selected portions of encoded multimedia data. Are logically organized into groups of standard transmission frames. Selecting the portion of encoded multimedia data includes selecting substantially all audio portions, selecting substantially all video portions including video header information, and each including video header data. Selecting a sequence of video portions immediately following the video portion, wherein the number of portions in the sequence depends on a predetermined bit rate of the second transmission. Selection map data and / or unequal error correction data may each be transmitted in the same order that the encoded multimedia data portions from which they were generated are transmitted. Alternatively, the selection map data and / or unequal error correction data may be transmitted in an interleaved order with respect to the order in which the encoded multimedia data portions from which they were generated are transmitted.

  The enhancement data for each group of standard transmission frames may be organized into a plurality of fixed size enhancement data transmission portions. A corresponding fixed size third error correction portion may be generated for each enhancement transmission portion. An enhancement data stream of fixed size enhancement transmission frames may be generated by a transmitter, each of a number of enhancement transmission frames being one of the enhancement data transmission portions and a group of standard frames. One of the third error correction parts. The third error correction portion in each enhancement transmission frame is for error correction of enhancement data included in the same enhancement transmission frame.

  Each enhancement data transmission portion may include a fixed size portion of selection map data and a fixed size portion of further unequal error correction data. Alternatively, all selection map data may be sent to each other in subsequent sections of the enhancement data transmission portion, and all further unequal error correction data may be sent to other subsequent portions of the enhancement data transmission portion. May be sent to each other in different sections.

  The selected stream portion may include an audio portion and a video portion, and the selection selects substantially all audio portions, and selects all video portions including video header information, and header information. Including the selection of a sequence of video portions immediately following the video portion including the size of the sequence depends on a predetermined bit rate for transmission of the enhancement data stream.

  In the case where the packets are organized into multiple segments and the selected stream portion is a packet segment, the selected stream portion includes the packet header of the packet that includes the selected packet segment.

  The standard multimedia data stream uses the standard multimedia data stream to modulate the first analog carrier at the first carrier frequency and transmits the first modulated carrier through the physical medium By doing so, it may be transmitted through the first channel. The enhancement data stream may be transmitted over the second channel by using the enhancement data stream to modulate the second analog carrier with a second carrier frequency different from the first carrier frequency. is there.

  Further aspects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, with reference to the accompanying drawings. In the following description of the drawings, the same label in different figures indicates similar devices.

  FIG. 1 illustrates an exemplary embodiment of a multimedia transmitter 100 of the present invention. The receiver 110 provides multimedia data to the signal processor 112. A standard multimedia data stream is provided by receiver 110 alone or in combination with signal processor 112. A standard stream includes encoded multimedia data and uniform error correction data. Uniform error correction data provides substantially the same error correction robustness for each portion of the encoded multimedia data.

  Receiver 110 may include, for example, an input that receives multimedia data, a media drive that reads the multimedia data from a record carrier, and a camera and microphone that receives the multimedia data from the environment. In the case where the receiver receives a standard multimedia data stream or the signal processor generates error correction data and formats the encoded multimedia data and error correction data into a standard multimedia stream. In the case where the receiver receives the encoded multimedia data or the signal processor encodes the raw data into the encoded multimedia data, the receiver converts the raw multimedia data It may only be offered.

  The signal processor 112 selects certain stream portions of the standard multimedia data stream and does not select other stream portions of the standard multimedia data stream. This selection depends on the importance of the type of data contained in the stream part to the quality of display of the multimedia data. The signal processor also generates selection map data indicating which stream portion has been selected. The signal processor also generates further unequal error correction data for the selected stream portion and does not generate further unequal error correction data for the other unselected stream portions.

  The transmitter 114 transmits the multimedia data stream to the first channel and transmits enhancement data including selection data map data and further unequal error correction data to the second channel. The second channel will be a different channel than the first channel. Thus, both uniform error correction data and unequal error correction data are provided for selected portions of the standard stream, and at least uniform error correction data is part of the standard stream that is not selected. Supplied about.

  FIG. 2 illustrates a portion 120 of an exemplary standard multimedia data stream. The standard stream matches, for example, the proposed ATSC DTV standard or the proposed DVB standard. A stream may consist of standard transmission frames of a continuously fixed size. Each standard frame includes a fixed size multimedia data portion 122 of the encoded multimedia data, and uniform error correction data used to error correct the encoded multimedia data. Followed by a uniform error correction portion 124 of fixed size. The standard error correction data may be, for example, FEC (Forward Error Correction). The encoding may be, for example, MPEG type encoding (eg MPEG-2 encoding), in which case the encoded multimedia data is derived from a fixed size 188 byte elementary stream packet. Each packet has a packet header and a packet data portion, the packet header includes an ID, and the packet data portion includes encoded multimedia data. For a standard MPEG encoded stream, each multimedia data portion may contain an integer number of MPEG packets fixed. For television, a packet of an MPEG stream typically includes a video packet having a packet data portion containing only video data and an audio packet having a packet data portion containing only audio data.

  The error correction data in each standard frame is for error correction only of the encoded multimedia data in the same standard frame, or the encoded data in other standard frames It is for error correction of media. FIG. 3 illustrates a group of four standard frames in which uniform error correction data that error corrects the packets in an order different from the order of the packets in the standard frame is interleaved. For example, in FIG. 3, uniform error correction data B ′, C ′, and D ′ for error correction of each packet B, C, and D is a standard group of frame different from packets B, C, and D. Included in the frame.

  A channel is considered different when the transmission of a data signal on one channel is substantially independent of the transmission of the data signal on another channel. For example, in broadcast, channels are typically different electromagnetic spectrum frequency bands, and in TDMA cellular systems, different predetermined time slices of the same frequency band. In spread communications (such as a CDMA cellular system), the channel includes time slices in multiple frequency bands. However, a scheme for dynamically allocating the same channel to multiple transmitters depending on varying data rates is not considered to be a substantially independent transmission.

  For example, the transmitter 114 uses a standard multimedia stream to modulate a first analog carrier at a first frequency, and then uses an enhancement data stream to vary the first frequency from the first frequency. Modulate a second analog carrier with two frequencies and transmit the second modulated carrier to the medium. In this case, the medium is a substance capable of transmitting waves such as sound waves or electromagnetic waves. The transmitter may include, for example, a laser that transmits light waves through an optical fiber, or an antenna that transmits radio waves or microwaves through space.

  FIG. 4a shows an embodiment of a group of four standard transmission frames of a standard multimedia data stream with a selected portion of the standard stream indicated by letters. The portion of the standard stream that was not selected is blank. The selected portion may include a portion of uniform error correction data, or the selection may be limited to include only media data that is encoded as shown in FIG. 4a. . The selected portion may be an MPEG packet or a packet segment that is a subdivision of the MPEG packet. For example, if each packet contains 188 bytes, each packet is logically subdivided into 6 packet segments, with the first 5 packet segments containing 32 bytes each and the 6th packet segment containing 28 bytes It is out.

  The standard number of frames in a group (ie group size) depends on a trade-off between delay, buffering requirements and bandwidth efficiency. For example, a larger group of standard frames introduces a lot of delay in processing standard frames (and delay in processing enhancement data) and requires a larger buffer to hold the data, More efficient packaging of enhancement data resulting in higher bandwidth efficiency.

  FIG. 4b illustrates a first exemplary embodiment of the selection map data of the present invention, where the selection map data is the selected portion shown in FIG. 4a. In this embodiment, the selection map is a bitmap, where 1 indicates that the corresponding part of the standard frame has been selected and 0 indicates that the corresponding part of the standard frame has not been selected. Is shown. To simplify the present invention, 0 is not shown in FIG. 4b.

  FIG. 4c illustrates a first exemplary embodiment of unequal error correction of the present invention. FIG. 4c shows error correction data for error correcting the selected portion of FIG. 4a. For example, the error correction data A ′, B ′, and C ′ are for error correction of the packets A, B, and C selected in the standard frame of FIG. 4A, respectively.

  FIG. 4d illustrates another exemplary embodiment of the selection map data of the present invention where the selection map data is interleaved with respect to the order of the portions of the standard stream from which the selection map data was generated. For example, the first 4 bits in the first row of the selection bitmap of FIG. 4b indicate whether the first packet of each of the four standard frames has been selected.

  FIG. 4e illustrates another exemplary embodiment of unequal error correction data of the present invention, with unequal errors with respect to the order of the portions of the standard stream from which the unequal error correction data was generated. Correction data is interleaved. In FIG. 4e, the first two parts, unequal error correction data A 'and M', are for error correction of packets A and M, respectively. Alternatively, the selection map data is in the format shown in FIG. 4b and the unequal error correction data is in the format shown in FIG. 4e so that the unequal error correction data is related to the selection map data. Interleaved.

  In FIG. 1, the signal processor 112 may generate third error correction data for error correction of enhancement data. The third error correction data provides substantially the same uniform error correction for all enhancement data. In this case, the transmitter 114 transmits third error correction data with enhancement data through the second channel.

  The signal processor 112 may organize the enhancement data into enhancement data streams of fixed size enhancement transmission frames. FIG. 5 shows a portion of an exemplary embodiment of an enhancement data stream. Each enhancement transmission frame has a fixed size enhancement data transmission portion 132 containing enhancement data and a fixed size third error correction transmission portion 134 containing third error correction data for error correction of the enhancement data. Consists of In this case, the transmitter 114 transmits the enhancement stream to the second channel.

  The third error correction data in each enhancement transmission frame may be FEC data. The error correction data in each enhancement transmission frame is for error correction of enhancement data in the same enhancement transmission frame, or in a manner similar to the interleaving of error correction data in a standard frame in FIG. There is a case where the enhancement data in another enhancement transmission frame is error-corrected.

  6a and 6b are different illustrations for organizing selection map data and unequal enhancement map data into the enhancement data transmission portion of the group of enhancement transmission frames for the standard group of transmission frames shown in FIG. 4a. The exemplary embodiment is illustrated. The number of frames in a group of enhancement transmission frames depends on the number of frames in the corresponding group of standard frames and the ratio of the portions of the standard frames that are selected to provide further unequal error correction. In FIG. 6a, each of the three enhancement transmission frames includes a fixed size portion 142 of the selection map data of FIG. 4b, and the fixed size portion 144 of the unequal error correction data of FIG. This is followed by a third portion 146 of error correction data. In FIG. 6b, subsequent portions 150 and 152 of the selection map data are included in the first two enhancement transmission frames. The selection map data is followed by subsequent portions 154 and 156 of unequal error correction data. Typically, selection map data is much smaller than unequal error correction data.

  The signal processor 112 includes the most important data types for maintaining the quality of the multimedia presentation. The most important data part depends on the type of multimedia data contained in the standard data stream. Since audio data is typically a small percentage of multimedia data and audio is generally most important to understanding a multimedia presentation than other parts, the audio part should be selected. Make presentations unintelligible even with relatively small loss of audio data. For standard MPEG-based packet streams, audio packets are identified by packet ID. Also, since the header information is important for decoding other video data, the video portion including the header information should be selected. Video header information in a typical MPEG video stream includes a frame header, a slice header, a macroblock header, and a block header. For an MPEG based standard stream, the packet needs to be analyzed to identify the part containing the video header. Finally, the sequence of subsequent video portions (which immediately follows the video portion including the header information) should be selected, and the number of video portions in the sequence of video portions may depend on a predetermined criterion. is there. The predetermined criteria may include a ratio of packets that will receive enhanced protection, the ratio of packets being at least approximately to provide a predetermined bit rate of the second transmission. It is adjusted dynamically.

  When a standard multimedia signal consists of packets, the packet is logically subdivided into segments that are selected parts, and when a segment of the packet is selected, the packet header of the selected segment is also selected. This is because the packet header is important for decoding the packet.

  FIG. 7 illustrates a more detailed exemplary embodiment of the multimedia transmitter 200 of the present invention. The receiver 202 provides raw multimedia data. The encoder 204 converts raw multimedia data into encoded multimedia data. The error correction coder 206 generates uniform error correction data for the encoded multimedia data, and the uniform error correction data is substantially error corrected for each portion of the encoded multimedia data. Provides the same robustness. Multimedia 208 formats the encoded multimedia data and uniform error correction data and provides a standard multimedia data stream. The selector 210 selects one stream portion of the standard multimedia data stream, but does not select another stream portion of the standard multimedia data for further unequal error correction, and further unequal Selection map data indicating which stream portion has been selected for correct error correction is generated. The selection depends on the importance of the type of data contained in the stream portion for the presentation quality of the multimedia data. The error correction coder 212 generates further non-uniform error correction data for the selected stream portion indicated by the selection map data and does not generate other stream portions that were not selected. The multiplexer 214 formats unequal error correction data and selection map data with each other and provides an enhancement data transmission part. The error correction coder 216 generates third error correction data for error correction of the enhancement data transmission part. Multiplexer 218 formats the enhancement data transmission portion and enhancement error correction data with each other to provide an enhancement data stream. The data stream may be composed of enhancement transmission frames described above with respect to FIG.

  The transmitter 220 transmits a standard multimedia data stream to the first channel, the transmitter 222 transmits the enhancement data stream to the second channel, and the second channel is the first channel. Different.

  Although the elements of the embodiment of FIG. 7 are described in separate components, in an effective design, some of the components may be shared, and in commercial embodiments, the multimedia transmitter's It is expected that one part is realized by software and the other part is realized by hardware.

  FIG. 8 illustrates an exemplary embodiment of the multimedia receiver of the present invention that uses both uniform and unequal error correction data to error-correct a standard multimedia data stream. 230 is shown. Receiver 232 receives a standard multimedia data stream from the first channel, and the standard stream includes encoded multimedia data and uniform error correction data. The receiver 232 also receives enhancement data including selection map data and unequal error correction data from the second channel, and the second channel is different from the first channel.

  The processor 234 uses the further unequal error correction data to first error correct a portion of the standard stream according to the selection map data. The selection map data indicates which points of the standard stream will be corrected with the first correction and that other parts of the standard stream will not be corrected with the first correction. The processor 234 also secondarily corrects all encoded multimedia data using uniform error correction data, and the uniform error correction is performed for each of the standard stream multimedia data. Provides substantially the same robustness of error correction for Some multimedia that cannot be error corrected may be discarded. The transmitter 236 outputs encoded multimedia data that has been error corrected on the medium after the first and second error correction of the data. Transmitter 236 includes a display that provides multimedia data to the audience, a recorder that records the multimedia data on a record carrier, an optical laser transmitter that transmits the multimedia data through an optical cable, an antenna that transmits the multimedia data through space, and And / or may include other types of media capable of transmitting signals.

  Either uniform error correction or unequal error correction may be initially performed on each portion of the multimedia data. However, if a portion of uniform error correction data is selected for further unequal error correction, it should be error corrected before it is used for uniform error correction.

  The enhancement data received by the receiver 232 from the second channel may be in the form of enhancement data described to be transmitted by the transmitter 114 of FIG. 1 or the transmitter 222 of FIG. For example, the enhancement data may be accompanied by a third error correction or formatted into an enhancement transmission frame as described above.

  The output of the transmitter 236 may be a standard multimedia data stream that is error-corrected, or just error-corrected multimedia data without uniform error correction data.

  The signal processor 234 may decode the encoded multimedia data to provide raw multimedia data. In that case, the transmitter 236 may include a simple presentation device (eg, a television without an MPEG decoder) to provide the decoded multimedia data to the audience.

  FIG. 9 is a diagram illustrating a more detailed embodiment of the multimedia receiver of the present invention. The first receiver 252 receives a standard multimedia data stream from the first channel. A standard stream includes encoded multimedia data and uniform error correction data for error correction of the multimedia data. Uniform error correction data provides substantially the same robustness of error correction for each portion of the encoded multimedia data.

  The second receiver 254 receives enhancement data including selection map data and further unequal error correction data from the second channel. The second receiver receives third error correction data from the second channel. The second channel is different from the first channel.

  The first error correction unit 256 corrects the enhancement data using the third error correction data. A second error correction unit 258 provides a first error correction of the portion of the standard data stream according to the selection map data using further unequal error correction data. The third error correction unit 260 provides a second error correction of the multimedia data encoded using the uniform error correction data. The decoder 262 converts the encoded multimedia data (after the first and second error correction) into decoded (unprocessed) multimedia data. The transmitter 264 outputs the multimedia data decoded after the first and second error correction of the data.

  FIG. 10 is a flow chart describing a specific exemplary embodiment of the method of the present invention. At step 302, raw multimedia data is provided. Unprocessed “raw” means that the data has not yet been encoded. Raw data may be supplied from data capture devices such as cameras and microphones, or other known methods for supplying multimedia may be used. The raw data may be analog or digital data. In step 304, the multimedia data is encoded to provide encoded multimedia data. MPEG encoding may be used to compress video. There are a large number of currently used and proposed methods for encoding multimedia data that can be used in the present invention. Encoding may include digitizing analog multimedia data. In step 306, uniform error correction data is generated. Uniform error correction data is effective for error correction of encoded multimedia data. Uniform error correction data provides substantially the same robustness of error correction for all parts of the encoded multimedia data. In step 308, a standard multimedia data stream of continuous standard transmission frames is generated. Each standard frame includes a fixed size portion of the encoded multimedia, followed by a fixed size portion of uniform error correction data.

  In step 310, one stream portion of the standard multimedia data stream is selected and the other stream portion of the multimedia data stream is not selected. The selection depends on the importance of the type of data contained in the stream portion for the presentation quality of the multimedia data. In step 312, selection map data indicating which stream has been selected is generated. In step 314, further unequal error correction data is generated for each selected stream portion and not for other unselected stream portions. Thus, further unequal error correction data is provided for a more important part of the standard stream.

  In step 316, third error correction data is generated to error correct the enhancement data. The enhancement data includes selection map data and further unequal error correction data. The third error correction data provides substantially the same uniform error correction for all parts of the enhancement data. In step 318, an enhancement data stream of enhancement transmission frames of a fixed size is generated, each enhancement transmission frame having a fixed size portion of enhancement data and a fixed size of uniform error correction data. Including parts.

  In step 320, a standard multimedia data stream is transmitted on the first channel of the medium. In step 322, the enhancement data stream is transmitted on a second channel of the same or different media. The second channel is a channel different from the first channel.

  In step 324, a standard multimedia stream is received from the first channel. In step 326, the enhancement data stream is received from the second channel. In step 328, the enhancement data is error corrected using the third error correction data of the enhancement data stream. In step 330, the selected stream portion is error corrected according to the selection map data using further unequal error correction data. In step 332, all encoded multimedia data portions are error corrected using uniform error correction data.

  The present invention has been described above with reference to specific exemplary embodiments. Those skilled in the art will understand how to modify these exemplary embodiments within the scope of the present invention. The invention is limited only by the claims.

FIG. 2 illustrates an exemplary embodiment of a multimedia transmitter of the present invention. FIG. 3 illustrates a portion 120 of an exemplary standard multimedia data stream. FIG. 6 illustrates an exemplary group of four standard frames in which uniform error correction data for error correcting a packet is interleaved. FIG. 4a is a diagram illustrating an example of selection of portions in a group of four standard transmission frames of a standard multimedia data stream in the present invention. FIG. 4b is a diagram illustrating a first exemplary embodiment of selection map data for the selected portion of FIG. 4a. FIG. 4c is a diagram illustrating a first exemplary embodiment of unequal error correction data of the present invention. FIG. 4d illustrates another exemplary embodiment of the selection map data of the present invention in which the selection map data is interleaved with respect to the order of the portions of the standard stream from which the selection map data was generated. FIG. 4e illustrates another exemplary implementation of the unequal error correction data of the present invention in which the unequal error correction data is interleaved with respect to the order of the portions of the standard stream from which the unequal error correction data was generated. It is a figure which illustrates a form. FIG. 6 illustrates an exemplary embodiment of an enhancement transmission frame of the present invention. FIG. 6a is a first illustrative example of organizing selection map data and unequal error correction map data into an enhancement data transmission portion of a group of enhancement transmission frames for the group of standard transmission frames shown in FIG. 4a. It is a figure explaining an embodiment. FIG. 6b is a first illustrative example of organizing selection map data and further unequal error correction data into the group of enhancement transmission frames of the standard transmission frame shown in FIG. 4a. It is a figure explaining embodiment. FIG. 2 illustrates a more detailed exemplary embodiment of the multimedia transmitter of the present invention. FIG. 2 is a diagram illustrating an exemplary embodiment of a multimedia receiver of the present invention. It is a figure which illustrates further detailed embodiment of the multimedia receiver of this invention. 6 is a flowchart illustrating an exemplary embodiment of the method of the present invention.

Claims (26)

Encoded multimedia data and uniform error correction data for error correction of the encoded multimedia data, wherein substantially the same error occurs for each portion of the encoded multimedia data Providing a standard multimedia data stream including standard uniform error correction data providing correction;
Depending on the importance of the data type contained in the stream part for the quality of presentation of the multimedia data for further unequal error correction, a stream part of the standard multimedia data stream is selected. Not selecting other stream portions of the multimedia data stream;
Generating selection map data indicating which stream portion has been selected for the further unequal error correction;
Generating further unequal error correction data for the corresponding selected stream portion and not generating for other unselected streams;
A first transmission step of transmitting the standard multimedia data stream along with the uniform error correction data on a first channel;
A second transmission step of transmitting enhancement data including the selection map data and the further unequal error correction data on a second channel different from the first channel;
Both uniform error correction data and further unequal error correction data are transmitted for the selected stream portion, and only uniform error correction data is transmitted for the other stream portions.
A method characterized by that. Providing the standard stream comprises:
Providing raw multimedia data; and
Encoding the unprocessed multimedia data to provide encoded multimedia data;
Generating, for the encoded multimedia data, uniform error correction data that provides substantially the same error correction robustness for all portions of the encoded multimedia data;
Each standard frame includes a fixed size portion of the encoded multimedia data followed by a fixed size portion of uniform error correction data Generating the standard multimedia data stream comprising transmission frames;
The method of claim 1 comprising: The encoded multimedia data includes elementary stream packets;
The packet includes a packet header and a packet data part,
The packet includes a video packet and an audio packet, the packet data portion of the video packet includes video data, the packet data portion of the audio packet includes an audio packet,
Each standard transmission frame includes uniform error correction data generated to perform error correction on the encoded multimedia data included in the same standard frame,
The uniform error correction data includes FEC (Forward Error Correction) data,
The standard multimedia data stream conforms to the ATSC DTV standard or the DVB standard.
The method of claim 2. The method further includes generating third error correction data for error correction to the enhancement data that provides substantially the same uniform error correction for all of the enhancement data;
The second transmitting step includes transmitting the third error correction data through the enhancement data and the second channel.
The method of claim 1. The method is
A fixed size enhancement transmission frame including a fixed size portion of enhancement data including the selection map data and the further non-uniform error correction data and a fixed size portion of uniform error correction data. Further comprising the step of generating an enhancement data stream comprising:
The second transmitting step includes transmitting the enhancement data stream through the second channel;
The method of claim 4 further comprising: The multimedia stream includes an audio portion that includes audio data, and the selected more important stream portion includes substantially all audio portions;
The third error correction data included in each of the multiple enhancement transmission frames is for error correction to the enhancement transmission data composed of the same enhancement transmission frame.
The further unequal error correction data is transmitted in the same order as the portion of the standard data stream from which the error correction data was generated;
The uniform error correction data, the further unequal error correction data, and the third error correction data include FEC (Forward Error Correction) data.
The method of claim 5. Said first transmitting comprises modulating a first analog carrier at a first frequency using said standard multimedia data stream and transmitting the modulated carrier through the medium;
The second transmitting step includes a step of generating an enhancement data stream including the selection map data and the unequal error correction data, and a second different from the first frequency using the enhancement data stream. Modulating a second analog carrier at a frequency of and transmitting the second carrier through a medium;
including,
The method of claim 1. The standard multimedia data stream is organized into standard transmission frames of a fixed size,
The method is
Logically organizing the standard transmission frames into a number of consecutive standard transmission frame groups;
The selection map data and the further unequal error correction data for a group of consecutive standard transmission frames are logically combined into a corresponding group of a number of continuous enhancement data transmission portions of a fixed size. The step of organizing;
The second transmitting step includes transmitting the enhancement transmission frame.
The method of claim 4. For a group of enhancement data transmission parts, each enhancement data transmission part is a fixed-size part of the selection map data and the further unequal error for the corresponding group of consecutive enhancement transmission frames. Including a fixed size part of the correction data,
The method of claim 8. For a group of standard transmission frames, all of the selection map data is packed into successive sections of the enhancement data transmission part and the unequal error correction data is a subsequent series of sections of the enhancement data transmission part. Packed in the
The method of claim 8. Successive sections of the further unequal error correction data are interleaved with respect to the order of corresponding selected portions in a group of standard transmission frames;
The method of claim 8. The selected stream portion includes a video portion including video data and an audio portion including audio data;
Selecting the stream portion comprises:
Selecting substantially all of the audio portion;
Selecting substantially all video portions including video header information;
Selecting a sequence of video portions immediately following the video portion including header information;
The number of video portions in the sequence of video portions depends on a predetermined criterion associated with a bit rate predefined for the second transmission;
The method of claim 1. The stream portion is a fixed size packet, each packet includes a packet header and a packet data portion, the audio data is packed into a packet data portion of an audio packet, and the video data is a video packet Packed in the packet data part,
The video header information includes a frame header, a slice header, a macroblock header, and a block header,
The predetermined criteria includes a ratio of packets that will receive enhanced protection, and the ratio of packets provides at least approximately a predetermined bit rate for the second transmission. To be adjusted dynamically,
The method of claim 12. The standard multimedia data stream is organized into fixed size packets, each packet including a packet header and a packet data portion, and the audio data is packed into a packet data portion of an audio packet, Video data is packed into the packet data portion of a video packet, each of the packets being logically divided into a number of packet segments,
Selecting the multimedia data portion comprises:
Selecting substantially all packet segments of the audio packet;
Selecting substantially all packet segments containing video header information;
Selecting a sequence of packet segments including video data immediately following the packet segment including video header information;
Selecting a packet segment that includes a packet header of the packet for which the packet segment was selected;
The method of claim 12 comprising: Receiving the standard multimedia data stream from the first channel;
Receiving the selection map data and the unequal error correction data from the second channel;
A first error correction step of performing error correction on the selected stream portion according to the selection map data using the further unequal error correction data;
A second error correction step for error correction to the encoded multimedia data portion using the uniform error correction data;
The method of claim 1 further comprising: Encoded multimedia data and uniform error correction data effective for error correction to the encoded multimedia data, wherein the encoded multimedia data Providing a standard multimedia data stream including uniform error correction data that provides substantially the same error correction robustness for each portion of the multimedia data, and said quality of presentation for said multimedia data Depending on the importance of the data type contained in the stream part, select one stream part of the standard multimedia data stream and not select the other stream part of the standard multimedia data stream, which A selection mark indicating whether the stream part has been selected It generates Pudeta, signal processing means for generating an additional unequal error correction data for the selected stream portion, not generated for other streams that have not been selected,
The standard multimedia data stream is transmitted on a first channel, and enhancement data including the selection map data and the further unequal error correction data is transmitted on a second channel different from the first channel. Transmission means for transmitting;
A multimedia stream transmitter characterized by comprising: The signal processing means includes an input terminal for supplying the standard multimedia data stream;
The transmitter according to claim 16. Providing the standard multimedia data stream comprises:
Supply encoded multimedia data,
Generating uniform error correction data for the encoded multimedia data;
Generating a standard multimedia data stream that includes the encoded multimedia data and uniform error correction data;
The transmitter according to claim 16. The signal processing means includes an encoding input terminal for supplying the encoded multimedia data.
The transmitter according to claim 18. Providing the encoded multimedia data includes providing raw multimedia data, compressing the raw multimedia data, and supplying the encoded multimedia data;
The transmitter according to claim 18. The signal processing means includes an input terminal for supplying the unprocessed multimedia data;
The transmitter according to claim 20. A receiver for receiving raw multimedia data;
An encoder for compressing the raw multimedia data to provide encoded multimedia data;
A first error correction that generates uniform error correction data for the encoded multimedia data that provides substantially the same error correction robustness for each portion of the encoded multimedia data. Generating means;
A multiplexer that formats the encoded multimedia data and the uniform error correction data to provide a standard multimedia data stream;
For further unequal error correction, select one stream portion of the standard multimedia data stream, and not select the other stream portion of the multimedia data stream, for the quality of presentation of the multimedia data A selector that generates selection map data indicating which stream portion has been selected for the further unequal error correction, depending on the importance of the data type included in the stream portion;
Second error correction generating means for generating further unequal error correction data for the selected stream portion indicated by the selection map data and not generating for other unselected streams;
First transmission means for transmitting the standard multimedia data stream on a first channel;
Second transmission means for transmitting enhancement data including the selection map data and the further unequal error correction data on a second channel different from the first channel;
A multimedia stream transmitter. A standard multimedia data stream including encoded multimedia data and uniform error correction data is received from a first channel, and from a second channel different from the first channel, selection map data and Receiving means for receiving enhancement data including unequal error correction data;
Using further unequal error correction data, some parts of the standard stream are corrected with the first error correction and other parts of the standard stream are not corrected with the first error correction. Uniform to provide a first error correction to the standard stream according to the selection map data to indicate that each portion of the multimedia data of the standard stream has substantially the same error correction robustness Processing means for performing a second error correction on all the encoded multimedia data using correct error correction data;
Transmitting means for transmitting encoded multimedia data that has been error-corrected after performing the first and second error corrections on data;
A multimedia data stream receiver comprising: Encoded multimedia data and uniform error correction data for error correction of the encoded multimedia data, wherein each part of the encoded multimedia data is substantially the same A first receiver that receives a standard multimedia data stream from a first channel, including uniform error correction data that provides robustness;
A second channel that receives selection map data and enhancement data including further unequal error correction data from a second channel different from the first channel, and receives third error correction data from the second channel. A receiver,
A first error correction unit that performs error correction on the enhancement data using the third error correction data;
A second error correction unit that provides first error correction of a portion of the standard data stream according to the selection map data using the further unequal error correction data;
A third error correction unit that provides second error correction of the encoded multimedia data using the uniform error correction data;
An output for transmitting encoded multimedia data that has been error-corrected after performing the first and second error corrections on data; and
A multimedia data stream receiver comprising: Encoded multimedia data and uniform error correction data effective for error correction to the encoded multimedia data, wherein the encoded multimedia data A standard multimedia data stream in the first channel, including uniform error correction data that provides substantially the same error correction robustness for each portion of the multimedia data;
Which part of the standard stream is corrected using the further unequal error correction data, or other part of the standard stream is corrected using the further unequal error correction data Enhancement data in a second channel different from the first channel, including selection map data indicating no correction, and further unequal error correction data;
An associated signal characterized by containing. 26. A medium comprising associated signals according to claim 25 in different channels of the medium.

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